Spindle driving mechanism fob screw



June 30, 1942. C. A. RICH VEIAL 2,288,254

SPINDLE DRIVING MECHANISM FOR SCREW AND SIMILAR MACHINES Filed Feb. 26,1940 2 Sheets-Sheet 1 il kn-' .7 o 52- 92 i ms 9a O a a l Inv'entonsJune 30, 1942. c. A. RICH ET'A'L 2,288,254

SPINDLE DRIVING MECHANISM FOR SCREW AND SIMILAR MACHINES Filed Feb. 26,1940 2 Sheets-Sheet 2 Patented June 30, 1942 AND SIMILARMA Charles A.Rich and William E. Twamley, Providence, R. 1., assignors to Brown andSharpe Manufacturing Company, a corporation of Rhode Island ApplicationFebruary 2 6, 1940, Serial No. 320,752 12 Claims. (01. 74- 325) 1 Thepresent invention relates to improvements in automatic screw and similarmachines, and more particularly'to an improved driving mechanism for thework spindle.

The mechanism for driving the work spindle in machines of this generaltype conventionally comprises two driven elements, usually sprocketwheels or pulleys loose on the rotatable work spindle, and clutchingmeans interposed between the driven elementsshiftable to cause thespindle to be driven alternatively by one or the other of them. Theseelements are continuously driven the spindle clutch for imparting thedesired rateand direction of drive to the work spindle for theperformance of successive operations of different character on the samepiece. It will be understood that adjustments relating to the rate. anddirection of .drive of the driven elements are made preferably insetting up the machine for i I the particular job, and not while themachine is in actual operation because of the relatively heavy weightand speed of operation of the driving connections.

In driving mechanisms of this type previously developed, thenumber ofadjustments available both in the basic operating speed and in the ratioof operating speeds of the two driven elements in setting up the machinefor operation upon widely divergent types of work, has been seriouslyclutch, and thereby to provide a machine which is well adapted foruniversal use in metal cutting.

limited by the complexity of mechanism and by the relatively greatnumber of replacement parts required for effecting these changes; In theinterest of avoiding such complication, it has been the usual practiceto provide separate machines metals for which speed changes within arelatively fast range of speeds are required, andfor operating on steeland similar slow cutting metals in which speed changes within a muchslower range of speeds are required.

It is a principal object of the present invention to provide a variablespeed spindle drive adapted for use in machines of this general type,which is simplified and improved both in construction and mode ofoperation, and is readily adaptable for driving the work spindle over anextremely wide range of operating speeds, and in accordance with aconsiderably greater number of speed It is a further object of thepresent invention to provide in a variable speed spindle drive of thisgeneral description, a simple and readily accessible device forreversing the' direction of drive of one of the driven elements'on thework spindle with relation to the other, and in accordance with anydesired ratio of rotating speeds of said driven elements as may bedesired in accordance with the requirements of the work and the set-upof the operating tools in the machine.

More specifically, it is an object of the invention to provide a novelconstruction and arrangement of the mechanism for driving the two drivenelements with their associated clutching means on the rotary workspindle, in which a maximum number of changes may be made in the drivingrate of both driven elements, in the ratio of the driving rate of onedriven element with relation to the other, and in the'relative directionof rotation of the two driven elements through the interchangeablelocation of exchangeable spur. gears in two pairs on appropriate drivingcenters for effecting all of the above noted adjustments.

With these and other objects in view, the several features of theinvention consist the devices, combinations, and arrangement of partshereinafter described and claimed, which together with the advantages tobe obtained thereby will be readily understood from the followingdescription taken in connection with the accompanying drawings, in whichFig. 1 is a view in front elevation of a portion of an automatic screwmachine with a portion of thecasing broken away to illustrateparticularly the spindle driving mechanism, only so much of the machinehaving been disclosed as is believed necessary to illustrate, the

, connection of the present invention therewith;

- for working on brass and similar 'free cutting ratios as determined bythe position of the spindle 55 Fig. 2 is an enlargedidetail sectionalview taken on the line 2--2 of Fig. 1, illustrating particularly thespindle driving mechanism located in the base of the machine; Fig. 3 isa plan View of the spindle driving mechanism shown in Fig. 2, but

with the reversible driving connections between the two spindle drivingsprockets shown in a developed position for clarity of illustration; and

Fig. 4 is a detail sectional view on the line 44 one another.

dle clutch which may be of ordinary description ,keyed on the spindle,and arranged to be shifted axially into clutching engagementalternatively with either sprocket. It will be und'erstood that abeltand pulley drive may be substituted for the illustrated sprocket chainkand sprocket wheeldrive if so desired, the term wheel" as hereinafteremployed in the claims being intended to cover the use of either asprocketwheel or pulley The driven sprocket wheels are continuouslydriven by means of sprocket chains which pass around driving sprocketwheels forming part of the spindle driving mechanism located in themachine base. In accordance with the usual practice, applicants providea large and a small driving sprocket wheel providing an initial ratio offast and slow rotating speeds for the driven sprockets.

-driving mechanism has the advantage that a maximum number of changesmay beeffected in the basic driving speeds of both driving sprockets,

I and also in the driving speed ratio between the driving sprockets bymerely shifting the relative positions of the four gears comprising thetwo pairs. Furthermore, a single set of replacement gears may beemployed to effect desired changes both in the basic driving speed ofthe large sprocket and the small sprocket driven there-- from, and alsoin the driving speed ratio between the two sprockets. In this manner, avery large number of speed changes are possible with a relatively smallnumber of replacement gears. This may be illustrated as follows: witheach machine it is proposed to provide twelve change gears, which gearsin combination will render 132 available ,speeds. With this combinationof gears, in other words, there will be available 120 .low speeds incombination with twelve high speeds.-

Another feature of the invention consists in a "simplified and improvedarrangement of the spindle driving mechanism including the large andsmall driving sprocket wheels, their supportingshafts, and the changespeed driving mechanisms which is simple and compact in construction,and is also readily accessible by the operator for the replacement ofchange gears of either pair. In accordance with this feature of the invention, the two driving-sprockets are mounted on supporting shafts inaxial alignment with Driving connections to the large sprocket.supporting shaft include a short power shaft and a-pair of change gearsmounted in meshing relation respectively on the power shaft and largesprocket supporting shaft, these parts being located entirely at oneside of the large struction and arrangement of the driving mechanismdnwhich the ratio change driving connections to the small driving sprocketsupporting shaft pass through the axis of the large driving sprocket;there is the further advantage that the centers on which both pairs ofchange gears are mounted may be located relatively close together, sothat relatively small gears may be em ployed, and a compact constructionof the whole mechanism is achieved.

In accordance with another feature of the invention, applicants provideanovel and eflicient mechanism particularly adapted for use in a spindledriving mechanism of this description for reversing the direction ofdrive of one of the driven sprockets on the work spindle. In theillustrated construction, a pair of ratio change gears are arranged tobe mounted respectively on the small sprocket supporting shaft and oneither of two lay shafts which are located equal distances from the axisof rotation of the small sprocket, and are continuously driven inopposite directions from the large sprocket supporting shaft. In thepreferred form of the invention sprocket supporting shafts so that theircenters form an isosceles triangle; .the drive from .the

- large sprocket supporting shaft being taken through a'gear on saidshaft, a gear out of align- I ment therewith on one of the lay shafts,and a third gear on the other of said lay shafts of sufficient width formeshing engagement with both of said gears.

Referring more specifically to the drawings, Fig. 1' discloses .anautomatic screw machine which may be of ordinary constructioncom'prising with a casing ID, a rotary'hollow' work spindle l2 havingloosely mountedthereon two driven sprocket wheels l4 and I6 and a,clutch element l6 keyed to the shaft and arranged-to be shiftedalternatively into clutching engagement with one or the other of saiddriven sprockets l4 and I6 In accordance with the usual practice inthese machines, the position of the clutch I8 is automaticallycontrolled from a cam shaft 20 and shift cam 22 by means of a camactuated clutch shift lever 24 mounted on a stationary pivot 26 andhaving connection at its upper end with a clutch shifting collar 28-onthe clutch member I6. Also shown in Fig. 1 is a tool carrying turrethead 3|! and cross slide ways 32 of ordinary description. a

sprocket, and driving connections from one to the other of the sprocketsupporting shafts located entirely at the other side of the largesprocket, and including a second pair of ratio change gears mountedrespectively on a lay shaft driven from the large sprocket shaft and onthe small sprocket supporting shaft. With this con- The machine drive istaken from an electric motor 34, to a driving countershaft 36, andthence by means of a sprocket 38 on the armature shaft of the motor, asprocket chain 46, and a sprocket 42 on the countershaft 36. As shown inFigs. 1 and 3 of the drawings, the cam shaft 20 is driven from thecountershaft 36 through driving connections which include a gear on theshaft 36, and a gear 'l6,.meshing therewith carried on a shaft 48. Theshaft 20 is directly driven from the shaft .48 by means of a beltpassing over a pulley 6| on the shaft 46 and a pulley 53 on the shaft2|).

Applicants improved variable speed mechanism for driving the workspindle comprises a large driving sprocket wheel 52 connected by meansof a sprocket chain 54 with the driven sprocket wheel I, and a smalldriving sprocket wheel 66 connected by means of a sprocket chain 66 withthe driven sprocket wheel l6. sprocket wheels 52 and 66 are rigidlymounted on supporting shafts and 62 respectively, as best The drivinging shafts 88 and 62 are in axial alignment, be-

1185 64 in a bracket 66. The supporting shaft 68 is further supported atits outer'end in a ball bearing 68 formed in a wall 18 of the machinecasing. The supporting shaft 62 is similarly supported at its outer endin a ball bearing I2 carried in a wall 14 of the machine casing. The

. large driving sprocket 62 and its supporting shaft ing shaft 62 aredriven from the large sprocket supporting shaft 68 through drivingconnections which include two lay shafts 88 and 98 which are arranged inparallel relation to the aligned supporting shafts 68, 62, and withtheir centers equal distances from the shaft 68 in the form of anisosceles triangle. As will be further evident from shown in Fig. 3 ofthe drawings. These supporting supported at their adjacent ends in ballbeara an inspection of Figs. 2 and 3, the power shaft I6 is also inalignment with the lay shaft 88, so

that the distance between centers of the power shaft 76 and largedriving sprocket supporting shaft 68 is the same as that between the layshafts 88, 98, and small driving sprocket supporting shaft 62. The layshafts 88, 98 are continuously driven in opposite directions from thelarge sprocket supporting shaft 68 through gear connections comprising adriving gear 92 secured adjacent the right hand end of the shaft 88, a

gear 94 on lay shaft 98 arranged out of. alignmentwith gear-'92, and agear 96 on the lay shaft 88 which is of the same diameter as gear 94,but is of sufiicient width for meshing engagement with both the drivinggear 92 and gear 94. The small driving sprocket 56 and its supportingshaft 62 are arrangecr'to be driven alterna; tively in one or the otherdirection through the connections above described, by means of a pair ofchange gears 98 and I88, one of these gears,- as that indicated at 98,being mounted on a shaft 62, and the other of said gears, as thatindicated at I88, being supported on either of the lay shafts -88 or 98,depending upon the direction of drive which is desired for the slowspeed driven sprockwork in diameter is to be turned down and threaded toprovide a screw thread having diameter and 10 'turns to the inch. Inthis instance a ratio of three to one is employed. The spindle speedsfor the tumingand the subsequent threading operations are listed asfollows:

For brass4150 R. P. M. and 1390 R. P. M.

For steel-870 R. P. M. and 290 R. P. M.

In Example 2, it is assumed that the work also in diameter is to beturned down and threaded-to provide a screw thread with 16 turns to theinch. In this example, a ratio of spindle speeds of five to one isemployed; The actual spindle speeds for the turning andsubsequentthreading operations are given as follows:-

For brass-4150 R. M. and 840 R. P. M. For 'steel--870 R. P. M. and R. P.M.

In Example 3, it is assumed that a worm thread is being out in diameter,and with twelve turns to-the inch. In this example where a fine finishis required, a ratio of ten to one is employed, the actual speeds forthe. successive turning and threading operations being .listed asfollows:

For brass-4150 R; P. M. and 415 R. P. M. For steel-1640 R. P. M. and 164R. P. M.

.- ployed, it would be necessary to reverse the work direction to causethe die to back ofi the threaded portion of the work, such reversalbeing effected by the location of theselected spur gear I88 on the layshaft 98.- r

It will be understood that the invention is not limited to the specificembodiment shown, and that various deviations may be made therefromwithout departing from the spirit and scope of the appended claims. Q

-What is claimed is: I 1. For use in automatic screw and similarmachines, the combination witha work spindle, a pair of driven elementsloose on saidspindle, and means for clutching said driven elementsalternatively to drive-the spindle, mechanism for continuously drivingsaid drive'n elements including a driving element having connection witho'nedriven element, a se'conddriving ele-" ment having connection withthe other driven ing-a pair of exchangeable spur gears for driving bothof said driving elements from the prime mover at adjustable speeds,driving connections including a second pair of exchangeable spur gearslocatable for'driving one of said driving elements at adjustable speedsin alternate directions with relation to the other driving element, andsupporting centers for each pair of spur gears including alternativelyavailable reverse driving centers for said second pair of spur gears. 5

2. For use in automatic screw and similar machines, the combination.with a work spindle, a pair of driven elements loose on said spindle,and means for clutching said drivenelements alternatively to drive the.spindle, mechanismfor continuously driving said driven elementsincluding a driving element having connection with one driven element, asecond driving element.

having connection with, the other driven element, a prime mover, gearconnections including a pair of interchangeable spur gears for drivingboth of said driving elements from the prime mover' at adjustablespeeds, driving connections including a second pair of spurgearslocatable for driving one of said driving elements at adjustable speedsand in alternate directions with relation to the other of said drivingelements, and sup-' porting centers for each pair of spur gearsincluding alternatively available reverse driving element, a primemover, gear connections includcenters for said second pair of spurgears, the supporting centers for each pair of spur gears including saidreverse driving centers being arranged equal distances apart whereby allof said spur, gears are freely interchangeable to effect all of saidspeed and directional adjustments.

, 3. For use in automatic screw'and similar ma- .chines, the combinationwith a work spindle, a,

pair of driven'wheels loose on said spindle, and means for clutchingsaid wheels alternatively to drive the spindle, driving means for saidwheels ing shaft having connection with one of said driven wheels,a:smalldriving wheei and a supporting shaft in axial alignment with saidlarge having connection with one of said driven wheels, iii

a second driving wheel and a supporting shaft having connection with theother of said driven wheels, means for driving said'first driving wheeland shaft including a pair of interchangeable spur gears, a pair of layshafts arranged parallel to said second driving wheel supporting shaftand equi-distant-therefrom, means connecting 581d lay including a largedriving wheel and a supportshafts to be driven by the first drivingwheel supporting shaft in opposite directions, and a pair ofexchangeable spur gears arranged on said second wheel supporting shaftand on either of said layshafts'in meshing relation for driving said 1second driving wheel alternatively in opposite didriving wheel'and itsshaft and having connection with-the other of said driven wheels, meansfordriving said'large driving wheel and shaft, a lay shaft arrangedparallel to said supporting shafts, gears connecting the lay shaft tobetively to drive the spindle, driving means for said wheels including alarge driving wheel and a supporting shaft having connection with one ofsaid driven wheels, a small driving wheel and a supporting shaft inaxial alignment with said large driving wheel and shaft and havingconnection withthe other of said driven wheels,

means for drivingsaid large driving wheel and. shaft including a powershaft, and interchangeable spur gears on said power shaft and on saidlarge driving wheel supporting shaft in meshing relation, a lay shaftarranged parallel to said means for clutching said wheels alternativelyto rections with relation to said first driving wheel.

'7. For use in automatic screw and similar machines, the combinationwith a work spindle, a pair of driven wheels loose on said spindle, and

drive the spindle, and driving means for said wheels including a drivingwheel and supporting shaft having connection with one of said drivenwheels, a second driving wheel and supporting shaft in axial alignmentwith said first driving wheel and shaft and having connection with theother of said driven wheels, means for.

driving said first driving wheel and shaft, a pair of lay shaftsarranged parallel to said supporting hafts and equidistant therefrom,gears conchines, the combination with a work spindle, a

pair of driven wheels loose on said spindle, and means for clutchingsaid driven wheels alternatively to drive the spindle, driving means forsaid wheels including a large driving wheel and a supporting shafthaving connection with one of said driven wheels, a small driving wheeland a supporting shaft in axial alignment with said large driving wheeland shaft and having connection with the other of said driven wheels,means for driving said large driving wheel and shaft including a powershaft, and interchangeable spur gears on said powershaft and largedriving wheel supporting shaft in meshing relation, a lay shaft arrangedparallel to said supporting shafts, gears connecting the lay shaft to bedriven by the large wheel supporting shaft,

and exchangeable spur gears arranged on the.

lay shaft and on the small wheel supporting shaft in meshing. relation,said power shaft and lay shaft being located equal distances from theaxes of said supportingshafts to permit the interchanging of said pairsof spur gears.

6. In automatic "screw and similar machines,

the combination with a work spindle, a pair of driven wheels'loose onsaid spindle, and means for clutching said wheels alternatively to drivethe spindle, and driving means for said wheels including a driving wheeland a supporting shaft necting the lay shafts to be driven in oppositedirections from the first wheel supporting shaft, and exchangeable spurgears arranged on the second wheel supporting shaft and on either ofsaid lay shafts in meshing relation to drive the small wheel shaftalternatively in opposite directions with respect to the first drivingwheel and its shaft.

8. For use in, automatic screwmachine, the combination with a workspindle, a pair of driven wheels loose on said spindle, and means forclutching said driven wheels alternatively to drive the spindle, anddriving means for said' wheels including a driving wheel and supportingshaft having connection with one of' said driven wheels, a seconddriving wheel and supporting shaft in axial alignment with said firstdriving w eel and shaft and having connection with the other of saiddriven wheels, a pair of lay shafts and a power shaft arranged parallelto said supporting shafts and equi-distant therefrom, gears connectingthe lay, shafts to be driven in opposite directions from the first wheelsupporting shaft, exchangeable spur gears arranged on the power shaftand on the first wheel' supporting shaft in meshing relation, andexchangeable spur gears similarly arranged on the second wheelsupporting shaft and on either of said lay shafts in drive the spindle,and driving-means for said wheelsincluding a large driving wheel and asupporting shaft having connection with one of said driven wheels, asmall driving wheel and a supporting shaft having connection with theotherof said driven wheels, means for driving said large wheel and'shaftincludinga pairgoffinterchange-- able spur gears, a pair of layshaftsarranged parallel to said small driving wheel supporting 2,288,254shaft and equi-distant therefrom, gears connecting said lay shafts to bedriven by the large driving wheel supporting shaft in oppositedirections, and a pair of exchangeable spur gears arranged on said smallwheel supporting shaft and on either of said lay shafts in meshingrelationfor driving the small driving wheel alternatively spur gears. onthe power shaft and on the large wheel supporting shaft in meshingrelation, a pair of-lay shafts parallel to the upporting shaftseq'ui-distant therefrom and from each other, and

with one of saidlay shaftslin axial alignment with said power shaftwhereby all of said spur gears are freely interchangeable, means fordrivin opposite directionswith relation to said large driving wheel. p

10. For use in automatic screw and similar machines, the combinationwith a work spindle,

- a pair of driven wheels loose on saidspindle, and

shafts, gears connecting said lay shafts to be driven by the large wheelsupporting shaft and in opposite directions, and exchangeable spur,gears arranged on the small wheel supporting shaft and on either of saidlay shafts in meshing relation for driving the small driving wheeltionto the large driving wheel.

11. For use in automatic screw and similar machines, the combinationwith a work spindle,

alternatively in opposite directions with relaa pair of driven wheelsloose on said spindle, and

means for clutching said wheels alternatively to drive the spindle, anddriving means for said wheels including a large driving wheel and asupporting shaft having connection with one of said driven wheels, asm'alldriving wheel and a supporting shaft in axial alignment with saidlarge driving wheel and shaft and having connection with the other ofsaid driven wheels,

means for-driving said large driving wheel andshaft including a powershaft, and exchangeable ing the lay shafts in opposite directions fromthe large wheel supporting shaft including a gear-on the large wheelsupporting shaft, 9. gear on one of the lay shafts out of alignmenttherewith-,

and a gear on the other of said lay shafts meshing with both of saidgears, and exchangeable spur gears arranged on the small wheelsupporting shaft and on either of said lay shafts for driving the smalldriving wheel alternatively inopposite directions with relation to thelarge driving wheel. I

12. For use in automatic screw and similar machines, thecombination witha work spindle,

a pair of driven wheels loose onsaid spindle, and means for clutchingsaid driven wheels alternatively to drive the spindle, driving means forsaid driven wheels including a'driving wheel-and a supporting shafthavingconnection with one of said driven wheels, a second driving wheeland a supporting shaft in axial alignment with said first-mentioneddriving wheel and its shaft and having connection with the other of saiddriven wheels, a prime mover, gear connections including a pair ofexchangeable spur gears and-driving centers for the same for drivingsaid first-mentioned supporting shaft and wheel, and driving connectionfor driving the last-mentioned supporting shaft and wheel from thefirst-mentioned supporting shaft and wheel including a second pair bfspur gears locatable for driving said second shaft from ,the. firstshaft at adjustable speeds and in alternate directions with relation tosaid first-mentioned supporting shaft and wheel, and alternativelyavailable reverse .driving centers for-said second pair of spur gears.

CHARLES A. RICH. WILLIAM E. TWAMLEY.

